Aortic graft device

ABSTRACT

An aorta graft device comprising a primary graft part having a proximal end and a first connecting means at a distal opening, wherein the primary graft part has an anchoring area positioned between an ascending portion extending to said proximal end and a descending portion extending to said distal opening. Furthermore, the ascending portion is corrugated, and the descending portion is at least partially non-corrugated.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of European Patent ApplicationNo. 01610036.4 filed Mar. 27, 2001.

TECHNICAL FIELD

[0002] The present invention relates to a medical device and, inparticular, to an aorta graft device.

BACKGROUND OF THE INVENTION

[0003] An aorta graft is an endovascular prosthesis for placement inaorta in a weakened area, such as at an aneurysm of the abdominal aorta.An aortic aneurysm is an abnormal dilation or enlargement of thearterial wall of the aorta. If the aneurysm is not treated, it canrupture and abruptly cause a fatal blood loss out of aorta into theabdominal or thoracic cavity of patient.

[0004] The aorta graft is normally made of a tube of pliable materialprovided with a stent for anchoring the graft in its intended positionwithin the blood vessel by exerting an outwardly directed radialpressure against the surrounding aortic wall. This requires in the areaof the stent a relatively healthy aortic wall that can withstand theradial pressure for years. Patients diagnosed with aortic aneurysms areoften in poor health due to other illnesses which increase the risk ofcomplications associated with an operation. Most prior art aorta graftsare for the repair of abdominal aortic aneurysms (AAA) involving thepararenal and infrarenal aorta. Examples of such grafts are described inU.S. Pat. Nos. 5,984,955 and 6,016,810. Many of these grafts arebifurcated and extend into the iliac arteries. Aortic grafts of thesetypes can typically be placed using transluminal, minimally invasive 10procedures where the graft is percutaneously introduced via a femoralpuncture site, and the entire procedure can be performed using localanaesthesia.

[0005] With respect to aortic grafts for the repair of thoracoabdominalaortic aneurysms (aneurysms in the descending thoracic aorta) andthoracic aortic aneurysms (aneurysms in the ascending thoracic aortaincluding the aortic arch) only a few proposals for minimally invasiveprocedures have been made.

[0006] U.S. Pat. No. 6,099,548 proposes to advance the graft into theascending thoracic aorta and to lock it to the aortic wall by expandinga stent in the proximal end of the graft. However, adjacent the heartthe flow rate of blood through aorta is so high that the risk ofdislocation of the proximal stent is considerable.

[0007] In a particularly lethal kind of aortic aneurysms the aortic wallis dissected to form a bogus lumen that establishes a parallel flow pathfor blood. The only method of repair is open surgery. In a so-calledelephant trunk procedure a stented distal end of a secondary graft partis fixed in the descending aorta, and the proximal end of the secondarygraft part is sutured to a primary graft part that is placed in theascending aorta and anastomosed to the branch arteries carotis communis,subclavia and truncus brachiocephalicus.

[0008] During the operation the patient is subjected to cardiac arrestand systemic circulatory arrest, and although the patient has beencooled to a very low body temperature, such as 16° C., and selectivecerebral perfusion is performed, the duration of the operation is acritical factor.

[0009] Dissections of type A where the aortic wall dissection isinitiated in the ascending aorta pose a particular problem. With theprior art techniques the mortality is 75% within 24 hours of initiationof the condition and 90% within one week. The surgeon thus has extremelyshort time to prepare and perform the surgery.

SUMMARY OF THE INVENTION

[0010] A purpose of the present invention is to improve the efficiencyof the surgical repair of implanting the aortic graft device.

[0011] With a view to this the aortic graft device according to theinvention is characterized in that the primary graft part has ananchoring area positioned between an ascending portion extending to saidproximal end and a descending portion extending to said distal opening,that the ascending portion is corrugated, and that the descendingportion is at least partially non-corrugated.

[0012] The positioning and anchoring of the primary graft part can beginimmediately after cardiac arrest has been obtained. The corrugations onthe ascending portion of the graft facilitates setting of the ascendingportion in a curvature following the path of the ascending aorta in theparticular patient. This saves some time. A further major time saving isobtained in that the primary graft part is the first one to bepositioned in the patient. After anchoring the primary graft part to theaortic wall, the ascending portion of the graft can be located in theascending aorta and the descending portion of the primary graft part canbe left hanging loose in the descending aorta. Time consuming suturingof the secondary graft part to the primary graft part is avoided whichmarkedly reduces the duration of the critical part of the operation inwhich cardiac arrest and systemic circulatory arrest are required.

[0013] The non-corrugated area on the descending portion makes itpossible to connect the descending portion of the graft to a secondarygraft part or to the aortic wall at a subsequent operation. When thesurgeon has performed the anchoring of the primary graft part he isaware of the time consumed and he can decide to insert a secondary graftpart right away if time allows this, or to postpone placement of asecondary graft part or an alternative connection of the distal end ofthe primary graft part to the aortic wall to another operation. Thesurgeon also fixes the proximal end of the primary graft part to thedesired site of the aortic wall in the ascending aorta.

[0014] The anchoring area positioned between the ascending and thedescending portions of the primary graft part make it possible for thegraft to be fixed to a portion of the aortic wall in vicinity of thethree branch arteries on the aortic arch. The anchoring can be made tothe distal side of the arteria subclavia at least at the upper portionof the aortic arch and possibly in an annular pattern following theaortic wall.

[0015] In an illustrative embodiment, the descending portion of theprimary graft part is non-corrugated at least at said first connectingmeans, and preferably along its full length from said anchoring area tosaid distal opening. The non-corrugated area makes it easier to obtain ablood tight connection between the primary graft part and the tubularmember connected to it.

[0016] The descending portion of the primary graft part is provided withat least one stent, and preferably provided with at least two stents,which are located near the anchoring area and at the distal opening,respectively. The stent resiliently acts on the descending portion tokeep it open and non-kinking.

[0017] In a further embodiment the descending portion of the primarygraft has a distal end area which is uncorrugated and unstented and hasa length of at least 20 mm. The distal end area can be utilized tocouple the primary graft to either a secondary graft or to the aorticwall. It is possible to perform suturing in the distal end area, but itis likewise possible to use the smooth surface character in the distalend area to obtain a pressure-tight sealing between the primary graftand the secondary graft.

[0018] The descending portion of the primary graft part is preferablysupported by a stent at least along the majority of its length. Bystenting, the descending portion is kept fully open, also when it issubjected to compressing or kinking actions on the exterior of thedescending portion which is hanging freely floating in the aortic vesseldownstream of the anchoring area. This is particularly useful when asecondary graft part is to be connected to the primary graft part atseparate surgery.

[0019] In order to facilitate handling and placement of the primarygraft at least the ascending portion of the primary graft part isprecurved. The precurved shape reduces the size of bending forcesrequired to keep the ascending portion in position during suturing ofthe anchoring area and thus minimizes the time spent on correcting thelocation of the primary graft part during suturing.

[0020] In a preferred embodiment, a wedge-shaped area of graft side wallin the ascending portion has been removed and the exposed opposite rimareas have been joined to each other. The removal of the wedge-shapedarea results in a distinct or sharp bend in the graft part at the placeof the removed material and allows on the one hand manufacturing of thegraft part as a straight tubular part with uniform properties and on theother hand the more sharp bend can be obtained in a comparatively easymanner.

[0021] It is preferred that the ascending portion has a length in therange of from 11 to 17 cm, that said descending portion has a stentedlength in the range of from 5 to 10 cm, and that said distal end areahas a length in the range of from 2 to 3 cm. These features make theprimary graft part quite flexible in the rather long corrugatedascending portion and well suited to accept different kinds of fixationmodes in the descending portion, such as fixation to a secondary graftpart which is fixed to the natural aortic wall, or fixation of thedescending portion directly to the natural aortic wall.

[0022] When a patient is suffering from a dissection of type A, thedevelopment of the dissection and the paths it follows can be somewhatunpredictable, and in order to be more certain that every part of thedissection is blocked at a particular location in the aorta, theanchoring area can comprise an annular area encircling the primary graftpart. This allows for a fixation of the graft to the aortic wall along afull circumference of the wall.

[0023] It is preferred that said annular area is uncorrugated andunstented and has a length of at least 10 mm. The surgeon can quicklyfix this annular anchoring area to the aortic wall because the area isfree from pre-manufactured corrugations and stents and has a length thatprovides easy access to a contact point between graft and wall when thesuture is to be applied.

[0024] The anchoring area can in an embodiment include a lateral areawhich extends away from the annular area in direction of the ascendingportion. This lateral area can be positioned next to the three brancharteries and quickly be fixed to the aortic wall.

[0025] In a further development of the latter embodiment the lateralarea is carrying a marking, such as a coloring distinct from theremainder of the primary graft part. The coloring makes it very easy andthus quick for the surgeon to position the primary graft part with thelateral area facing correctly in the cranial direction.

[0026] In yet a further development the lateral area includes a lateralopening so that the surgeon does not spend additional time for providingcommunication between the aorta vascular space inside the graft and theaortic branch arteries.

[0027] The primary graft part can be supplied in or be set into amounting state where the ascending portion has been everted into saiddescending portion to present said annular anchoring area as a rim areato be sutured to the aortic wall.

[0028] A dissection of type A can extend into the area of the heartvalve and depending on the actual circumstances, such as whether acoronary artery is involved in the dissection, it can be insufficient torepair only the aorta. If additional surgery is required on the heartvalve, the graft device preferably also includes an end portion with aheart valve.

[0029] When the graft device includes a heart valve it is preferred thatthe primary graft part has a proximal opening, and that the end portionwith the heart valve is a separate part to be fixed to said primarygraft part at said proximal opening. This division of the graft deviceallows the surgeon to split the surgery into separate rounds where thetime consuming fixation of the end portion to the heart and coronaryarteries can be performed while the circulatory system is functioning bya cardio-pulmonary bypass and appropriate cannulations. Then, in asecond round, the primary graft part can be applied after establishingsystemic circulatory arrest, but the duration of circulatory arrest isconsiderably shortened by performing a large part of the surgeryrequired during said first round.

[0030] As mentioned above, the descending portion of the primary graftpart can be connected to the aortic wall in different manners. In oneembodiment, the graft device includes a secondary graft part with asecond connecting means that by engagement with said first connectingmeans connects said secondary graft part to said primary graft part. Useof the secondary graft part can often be a preferred alternative tosuturing of the descending portion to the aortic wall. The secondconnecting means makes possible a quick establishment of theinterconnection between the parts.

[0031] This embodiment can be further developed so that the engagementinvolves geometrically interlocking parts on said first and secondconnecting means, respectively, preferably so that the engagement isenhanced when said secondary graft part is pulled in the distaldirection. The geometrical locking of the two parts can provide betterlong term durability of the graft device which continuously is subjectedto the pressure pulses produced by the heart beats.

BRIEF DESCRIPTION OF THE DRAWING

[0032] Embodiments of the present invention are explained in more detailin the following with reference to the highly schematical drawings, onwhich

[0033]FIG. 1 and 2 depict two embodiments of an aorta graft deviceaccording to the present invention,

[0034] FIGS. 3-8 illustrate an example of deployment of the device inFIG. 1, and

[0035]FIG. 9 illustrate another embodiment of the device according tothe present invention.

DETAILED DESCRIPTION

[0036] An aorta graft device illustrated in FIG. 1 is generallydesignated 1 and includes a primary graft part 2 and an optionalsecondary graft part 3. The primary graft part 2 is tubular and has aproximal end 4 with a proximal opening 5. In the present contextproximal is used for something located closer to the heart or to theside of the heart whereas distal is used for something located moredistant from the heart.

[0037] The primary and secondary graft parts are tubular and can be madeof a pliable material, such as expanded polytetrafluoroethylene (PTFE),woven polyester or another biocompatible material of long term stabilityin the vascular system. Graft materials are well known in the art andthe material can also include the biodegradeable strands as part of thematerial.

[0038] The primary graft part has an ascending portion 6 and adescending portion 7. An anchoring area 8 is positioned in between thetwo portions 6, 7. The ascending portion 6 is at least partiallycorrugated (crimped) or folded in order to promote setting of theascending portion in a curved shape and flexibility of the graft in use.

[0039] The descending portion 7 is at least partially non-corrugated,and it can be non-corrugated along its complete surface. It can ofcourse alternatively be corrugated along only part of its circumferenceand/or its length. The descending portion 7 can be unstented along itsentire length, but preferrably it is at least partially stented by astent 9 located at a distal opening 10. Stent 9 is of well knownconstruction. It can e.g. be a so-called Gianturco Z-stent or anotherstent of expandable or self-expandable type which typically is ofnitinol, stainless steel or another biocompatible material. Stent 9 istypically placed inside the tubular graft material, but canalternatively be placed on the outside of the tubular material which isthen fastened to the stent struts, or the stent can be integrated intothe graft material.

[0040] Next to distal opening 10 the descending portion has a distal endarea 11 which is unstented and can have a length l1 in the range from 3mm to 40 mm, preferably from 20 mm to 30 mm. Stent 9 can extendcontinuously from distal end area 11 to the anchoring area 8. Asdepicted in FIG. 9 there can also be used two (or more) separate stents9, 12 located at a distance from each other. The stent or stents keepthe anchoring area in a stretched tubular shape ready for suturing andkeep the distal opening in an open state that is accessible from thedistal part of the aorta. In FIG. 1 the stented length I2 of thedescending portion is in the range of 5 cm to 10 cm. The ascendingportion has a length I3 in the range from 11 cm to 17 cm. The diameterof the graft device is in the range from 22 mm to 38 mm, preferably from30 mm to 34 mm, such as about 32 mm. The tubular graft material hastypically an even diameter along its length when it is manufactured, andsome variations in diameter can result from the crimping of theascending portion. However, it is also possible to make the graft of twoseparate tubular parts of different diameter if the ascending portion isto be of a diameter different from the descending portion of the graftdevice.

[0041] At the lower (concave) side of the tubular graft a wedge-shapedarea of the material has been cut away and the rim areas 13 have beenjoined, such as by suturing.

[0042] The secondary graft part 3 has a connecting means 14 depicted asa stent in its proximal end. When the secondary graft part has beeninserted through distal opening 10 into descending portion 7 and hasbeen expanded, whether by self-expansion or balloon expansion, theconnecting means 14 engages with stent 9 acting as a first connectingmeans on the primary part. The engagement can be of the frictional typeproduced by the radially outward pressure from stent 14 on the inside ofthe descending portion, but it is preferred that the mutual engagementinvolves geometrically interlocking parts, such as hooks 15 on stent 9(FIG. 9). The hooks extend obliquely in the proximal direction. Thehooks penetrate the graft material of graft part 3 and engage with thestruts of stent 14 when the graft part 3 is pulled slightly in thedistal direction.

[0043] In the following description of embodiments the same referencenumerals are used for details of the same type.

[0044] In FIG. 2 the graft device also includes an end portion 16 with aheart valve. The stent 9 runs in a spiral pattern from one end to theother of the descending portion 7. The anchoring area includes a lateralarea 17 extending annularly around a lateral opening 18 to be positionedat the three major branch arteries from the aortic arch. Lateral opening18 can be part of the graft device as manufactured or it can be cut bythe surgeon after he has opened the patient and ascertained the actualdimensions and locations of the proximal end opening of the brancharteries. In the latter case the lateral area can have a marking 19,such as a coloring, clearly indicating where the upwards facing lateralanchoring area is located on the graft device. This allows the surgeonto immediately position the graft device correctly and also helps toensure that the cutting of the lateral opening or openings is only donein the unstented anchoring area. FIG. 9 illustrates an embodiment withthree lateral openings 18.

[0045] With reference to FIGS. 3-8 there is in the following shortlydescribed an example of how the aorta graft device can be deployed.

[0046] After cooling the patient down and exposing the aortic arcthrough a sternotomy and performing cardiopulmonary bypass or systemiccirculatory arrest the ascending portion of aorta is resected, therebyexposing an proximal end opening 21 on the descending aorta 22 and aproximal end area 23 at the three major branch arteries 24 and a distalend opening 25 at the heart valve 26.

[0047] The graft device is in a mounting state with the ascendingportion 6 inverted down into the descending portion 7 (FIG. 4). Thegraft device is inserted into the descending aorta and is placed with arim area 27 at the end opening 21 and then the rim area 27 on the graftis fixed to the aortic wall, such as by suturing 28 or stabling.

[0048] After fixing of the graft to the aortic wall the ascendingportion of the graft is inverted to the position illustrated in FIG. 5with lateral opening 18 located at the proximal end area 23. Then thisend area 23 is joined with the lateral anchoring area 17, such as bysuturing or stabling. At this point in time the surgeon can decide toinsert the secondary graft part through the proximal opening 5 and mountit in the ascending aorta and/or to the descending portion of theprimary graft part. In many cases the decision will be to postpose theplacement of the secondary graft part to a separate surgery in order toreestablish circulation as quickly as possible. Then the rim area at theproximal opening 5 is joined with the rim area at the distal end opening25, such as by suturing or stabling.

[0049] The graft device is then in the state illustrated in FIG. 6 wherethe circulation can be reestablished. The descending portion is hangingloose into the aorta. Depending on the condition and desires of thepatient it is then possible to proceed in alternative ways. Onepossibility is to open the patient from the side and secure the end area11 to the aortic wall, such as by suturing or stabling or stenting.Another possibility is to add the secondary graft part 3 which can bedone either by percutaneously introducing (e.g. femorally) andintraluminally advancing graft part 3 with a minimally invasiveprocedure or by performing open surgery where the patient is opened fromthe side and the secondary graft part is introduced after establishingsuitable cannulation and bypass.

[0050]FIG. 7 illustrates the introduction of the secondary graft part 3held in a radially reduced state in an introducer 29. When the proximalend 30 of graft part 3 is correctly located in the descending portion 7the proximal end 30 is released from or expanded by the introducer sothat the first and second connecting means are brought into securemutual engagement. Then a distal end 32 of the secondary graft part 3 islocated at the desired site of the aorta and is fixed thereto, either bysuturing or stabling or by stenting. FIG. 7 illustrates stenting with adistal most stent 31 in the distal end.

[0051] Details of the above mentioned embodiments can be combined intoother embodiments within the scope of the present invention.

What is claimed is:
 1. An aorta graft device comprising a primary graftpart having a proximal end and a first connecting means at a distalopening, wherein the primary graft part has an anchoring area positionedbetween an ascending portion extending to said proximal end and adescending portion extending to said distal opening, wherein theascending portion is corrugated, and wherein the descending portion isat least partially non-corrugated.
 2. An aorta graft device according toclaim 1, wherein the descending portion of the primary graft part isnon-corrugated at least at said first connecting means, and preferablyalong its full length from said anchoring area to said distal opening.3. An aorta graft device according to claim 1, wherein the descendingportion of the primary graft part is provided with at least one stent,and preferably provided with at least two stents, which are located nearthe anchoring area and at the distal opening, respectively.
 4. An aortagraft device according to claim 3, wherein the descending portion of theprimary graft has a distal end area which is uncorrugated and unstentedand has a length of at least 20 mm.
 5. An aorta graft device accordingto claim 1, wherein the descending portion of the primary graft part issupported by stent at least along the majority of its length.
 6. Anaorta graft device according to claim 1 wherein at least the ascendingportion of the primary graft part is precurved.
 7. An aorta graft deviceaccording to claim 1 wherein the ascending portion a wedge-shaped areaof graft side wall has been removed and the exposed opposite rim areasjoined to each other.
 8. An aorta graft device according to claim 4wherein said ascending portion has a length in the range from 11 to 17cm, wherein said descending portion has a stented length in the rangefrom 5 to 10 cm, and wherein said distal end area has a length in therange from 2 to 3 cm.
 9. An aorta graft device according to claim 1,wherein said anchoring area comprises an annular area encircling theprimary graft part.
 10. An aorta graft device according to claim 1,wherein said annular area is uncorrugated and unstented and has a lengthof at least 10 mm.
 11. An aorta graft device according to claim 9,wherein said anchoring area includes a lateral area extending away fromthe annular area in direction of the ascending portion.
 12. An aortagraft device according to claim 11, wherein said lateral area iscarrying a marking.
 13. An aorta graft device according to claim 11,wherein said lateral area includes a lateral opening.
 14. An aorta graftdevice according to claim 1, wherein a mounting state of said primarygraft part the ascending portion has been everted into said descendingportion to present said annular anchoring area as a rim area.
 15. Anaorta graft device according to claim 1 wherein the graft deviceincludes an end portion with a heart valve.
 16. An aorta graft deviceaccording to claim 15, wherein the primary graft part has a proximalopening, and wherein the end portion with the heart valve is a separatepart to be fixed to said primary graft part at said proximal opening.17. An aorta graft device according to claim 1, wherein the graft deviceincludes a secondary graft part with a second connecting means that byengagement with said first connecting means connects said secondarygraft part to said primary graft part.
 18. An aorta graft deviceaccording to claim 17, wherein the engagement involves geometricallyinterlocking parts on said first and second connecting means,respectively, whereby the engagement is enhanced when said secondarygraft part is pulled in the distal direction.